Zurich International School (ZIS) is an independent non-profit day school in Switzerland for students aged 3 to 18 in the greater Zurich area. Over 1,300 students from more than 50 countries are enrolled in the school. The school has two campuses: a Primary campus in Wädenswil for Early Childhood and Lower School students aged 3 to 11 and a Secondary Campus in Adliswil for Middle School students aged 11 to 14 and Upper School students aged 14 to 18. As of 2011 it is the largest international school in the Zurich area.